Appliance for tracing courses on charts.



N0- 830,'718. PATENTED SEPT.11, 1906. H. E. S. HOLT. APPLIANCE FORTRAGING COURSES ON CHARTS.

APPLICATION FILED NOV. 26, 1904.

4 SHEBTSSHEET 1.

mi f a PATENT ED SEPT. 11, 1906.

4 SHEETSSHEET 2 H. E. S. HOLT.

APPLICATION FILED NOV. 26, 1904.

APPLIANGE'FOR TRAGING COURSES 0N CHARTS.

Harold LWCIIZOI? N0- 830,718. PATENTED SEPT. 11, 1906. H. E. S. HOLT.

APPLIANCE FOR TRAOING COURSES ON CHARTS.

APPLICATION FILED NOV. 26, 1904.

4 SHEETSSHEET 3,

3 un \m u n \u\ n 110. 830,718. 11331111111) SEPT. 11, 1906.

H. B. s. HOLT. APPLIANCE FOR 11111011111 COURSES ON CHARTS.

APPLICATION FILED NOV.26,1904.

4 SHEETS-SEEET 4.

Wzwmygs. I I 1 florvafy-- UNITED STATES PATENT OFFICE.

APPLIANCE FOR TRACING COURSES ON CHARTS.

Specification of Letters Patent.

Patented Sept. 11, 1906.

Application filed November 26, 1904. Serial No. 234,418-

To all whom it may concern:

Be it known that I, HAROLD EnwAm) SHERWIN HOLT, a subject of the King ofGreat Britain and Ireland, residing at The Grange, Farnborough, in thecounty of l l ants, England, have invented a certain new and useful Apliance for Tracing Courses on Charts, 0 which the following is aspecification.

This invention relates to an apparatus for automatically tracing on achart the course of a vessel, or, conversely, if a course is marked on achart, enabling the vessel to be navigated along such course without theaid of landmarks or lights or without necessitating the usualcalculations.

The invention briefly consists in causing an indicating device, such asa pencil or pointer, to move relatively to a chart and in directionscorresponding to the course of the vessel, the movements of the pencilor pointer being eflected by suitable motive power, such as by electricmotors, which not only impart the necessary motion to the pencil, butcontrol the direction taken by it, the power or influence of the variousmotors being adequately regulated by controllers which are operatedaccording to the direction and speed of the vessel and of prevalenttides, winds, or currents, ascertained by suitable indicators.

In order that the inventionmay be properly understood, reference will bemade to the accompanying drawings, wherein Figure 1 is a diagramillustrating the principle of the invention, while Figs. 2, 3, and

3' illustrate in sectional elevation and plan one practical embodimentof the invention, Figs. 3, 3 forming one complete view and Fig. 2 beinga section on the line 2 2, Fig. 3. Fig. 4 is a detail elevation of themain rheostat and accessory parts.

Referring first to' the diagram, Fig. 1, a

' represents the indicating device, in the form of either a pencil orpointer, which is to be moved over the chart to either indicate orfollow the course taken or to be taken by the ship. In order to impartthe necessary movement to the ointer, it is influenced b four motors N SW, each of which is ten ing to move it'in a direction on the chartcorresponding to the four cardinal points of the compass. It will thusbe understood that if the influence of all the motors is equal at anytime the pointer will remain stationary, whereas by varying theinfluence of any one or more of the motors the direction of travel ofthe pointer may be altered at will. Any suitable transmitting medium maybe em ployed between the motors and the pointer.

n the diagram it is assumed that screws of fine pitch are adopted, one,0, driven b the E and W motors through suitable di erential gear 6, andthe other, d, by the N and S motors, also through suitable differentialgear a. It will be clear that the speed and direction of rotation ofeither screw will depend upon whether one or other of the motors of itspair is running the faster, and accordingly as the speeds of the variousmotors are varied so will the direction and speed of'travel of thepointer be varied. Now in order that such travel of the pointer shallcorrespond with the travel of the ship it is necessar that the speed ofthe motors shall be control ed by some means regulated in turn accordingto the direction of the ships travel, the speed of same, and the speedand direction of any currents, tides, or winds. This may be accomplishedby varying the resistances in circuit with the field-windings of themotors. For

- instance, as indicated in the diagram, Fig. 1,

a main rheostat fitted with a contact-arm f, and connected at points N SE W with the respective motors N S E W, is placed in the batter-circuit, and the contact-arm f is move over the rheostat whenever thecourse of the ship is altered, so as to always point due N, as indicatedby a compass-needle. The rheostat may be graduated and marked off sothat the compass-needle directly indicates the direction of the shipscourse. For exam 1e, sup ose the rheostat is so set that a 11116 t roughS is parallel to-the fore-andaft axis of the ship, then if the ship isturned until the compass-needle is pointing to N on the rheostat theships course will be due north, and if to IE it will be due east, and soon. Since the speed of each motor depends on the resistance in itscircuit, and this is varied according to the position of the arm f, itwill be clear that if the contact-arm f is always moved so as to followup and coincide with the needle the speed of the respective motors willbe proportionately varied, so that the pointer a will travel in adirection corres ending to that-of the ship. In order that a lowance mabe made for variations in the speed of the s ip, a second rheostat g isrovided in the batter circuit, so as to a cot all the motors equa l andsimilarly. In order to allow for ti es, currents, or winds,

'other rheostats h and tare provided, one, It, for the direction of thecurrent, bein arranged and connected at points N S, W to additionalfield exciting-coils on the vari: ous motors N S E W, and the other, 'i,being a simple rheostat for the speed of the current,

- ascertained in any convenient manner.

The'principle of the invention beingvdel scribed, reference will now bemade to on a nut or block I), through which is thread-' ed a screwedshaft dof fine pitch, the shaft d being driven by motors N S throughdifferential gear'e to effect a travel of the pointera across the chart.The shaft d and-its motors are all carried u n a bridge I, which isadapted to slide on t e table '7; at ri ht angles to the shaft under theinfluence 0 two screwed shafts c,

gea

range so that both shafts 0 always rotate similarl The motors E-W thuseffect a travel of t e inter in a direction at ht angles to that eectedby the motors N pointer in a north or south direction on the chartand the motors E W in an east or westdirection. By this arrangement,therefore, the pencil or pointer a may be moved in any desired direction.by accordingly controlling the speeds of the various motors. Thesespeeds are controlled aS-hereinbefore mentioned, according to the speedand direction of the ship and also of any prevalent tides,

7 currents, or winds, this in turn being preferably accomplished also,as hereinbe fore mentioned, by regulating the resistances in circuitwith the field-windings of the motors. The rheostats for effecting thecontrol are shown, by way of example, arranged on an extension of thechart-table in F1 3. It is obvious, however, that they may earranged inany part of the chart-room or vessel. The are indicated by similarletters to those mar ed on Fig. 1, before referred to. In order to beable to easily and accurately adjust the handle or arm'f, an arcuatescale n is car-- ried on the end thereof with its zero-mark at themiddle point'z. A'lamp 0, also carried on the arni-f, throws a spot ofli ht onto a small mirror p, which is carried ri dly on the spindle ofthe magnet-needle q. his spot of hght is reflected onto the scale n, asshown in to this ,form' a pointer orright to left of. the'table as- 'venby motors E and W through differential gear a and suitable'intermediate1n, the latter being of 'course arthat is to say, the motors N S effectthe travelof the- Fig. 4, which is an elevation of this instrumentlooking in the direction of the arrow X, Fig. 3. The frame 1, in whichthe magnetneedle is pivoted, is screwed into the central boss of the armf and moves with it so that the frame never obstructs the path of thebeam of light. When the ships course is altered, the arm f must be movedround so as to' keep the-spot of light on the zero-mark on the scale n.

It is to be.u nderstood that the'apparatus above described is only oneractical embodiment of the invention an 'pendently arranged with regardto the compass- -that is to say, the compass-needle, with its mirror,may be arranged to throw a spot of light on a scale arr ed around thecabin, preferably near the roo and the navigating that the detailsthereof ma be considerably modified-for. instance t e ,m'ain'rheostatmay be indeofficer in cha e of the rheostat can move the handle thereoto cor'res nd with the movements of the spot of light, or the rheostatmay be formed 'on the scale and a small slidblock be made to follow thespot.

0 insure a uniform load on the motors and accurate variations of speedproportionate-to varyin resistances, the motors may be wound asuynamotors (motor-transformers) and the c rrent generated run into aresistance. tors is as follows: A wide range of s eed is necessary inthejmotors, as not onl as the speed of eachinotor of the air to bevaried relatively to the other in or er to 've pro r direction to thepencil, but also y anot er separatevariable resistance common to allfour motors the speed of all four is varied simultaneously according tothe screw revolution s, (or calculated dead-water s ed of the ship.)With such wide ranges 0 speed the friction of the actuating mechanismwould vary considerably, and consequently the load on the motors, Bywinding the motors as dynamotors or motor-transformers the current fromthe dynamo portion of the armatures can be run into a-fixed'resistance,thus giving a steady load. This load should be much glrleater than theload caused by internal 'ction, so that the variations of the latter arenegligible.

A dynamotor or motor-transformer may be constructed in two ways. -Eithertwo separate armatures and commutatorsmay be mounted on one shaft runninbetween The object of using the dynamo-.

two pairs of field-magnets, in whic case one armature will run as amotor and the other armature, which will generate current, as a dynamo,or one armature may be wound with two separate circuits and twocommutators, one taking current and driving the armature as a'motor,while the other generates current as an armature.

To make the apparatus adjustable for charts of different scales, themotors may be connected up through different gear-wheels, or anotherexternal'resistance may be put in the circuit and varied according tothe scale of the chart in use.

The a paratus may, if desired, be used converse y-that is to say, acourse may be marked on the chart and the vessel navigated so that thepencil follows this mark, and in consequence the vessel will befollowing the desired course. In this case it will be necessary for thehelmsman to receive orders from the navigating officer in charge of thevarious rheostats, who will operate the same in the required manner toretain the pointer on the course marked out. He will order the helmsmanto steer to port or starboard accordingly as the spot of light on thescale n moves away from the zeromark as he works the rheostats. He will,in fact, have to see that however he operates the rheostats the ship issteered to maintain the spot of light on the zero-markthat is, howeverhe may move the rheostat-arm f the ship must be steered to bring thatarm in a position point ing due N.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is 1 1. Apparatus for indicating the course ofa vessel, comprising an indicating device, independent mechanisms fordriving the indicating device in two mutually perpendicular directionsacross a chart, electric motors for drivin said mechanisms and rheostatsfor contro ling the motors according to the speed and direction of thevessel and of prevalent tides, currents and winds.

2. Apparatus for indicating the course of a vessel, comprising anindicating device, independent mechanisms for driving the indicat ingdevice in two mutually perpendicular directions across a chart, electricmotors for driving said mechanisms, a rheostat for controlling themotors according to the direction of the vessel, a compass-needlesupported above the center of the rheostat and an arouate scalesupported on the arm of the rheostat for the purposes hereinbefore setforth.

3. Apparatus for indicating the course of a vessel, comprising anindicating device, independent mechanisms for driving the indicatingdevice in two mutually perpendicular directions, two electric motors anddifferential gear for driving said mechanisms, a rheostat forcontrolling the motors according to the direction ofv the vessel, acompass-needle pivoted centrally above the rheostat, and an arcuatescale upon the'arm of the rheostat, for the purpose hereinbeforedescribed.

4. Apparatus for indicating the course of a vessel, comprising anindicating device, independent mcchanisms for driving the indicatingdevice in two mutually perpendicular directions, two electric motors anddifferential gear for driving said mechanisms, a rheostat forcontrolling the motors'according to the direction of the vessel, acompass-needle pivoted centrally above the rheostat, and an arcuatescale upon the arm of the rheostat, the needle carrying a mirror adaptedto reflect a spot of light upon the scale for the purpose hereinbeforedescribed.

5. Apparatus for indicating the course of a vessel, comprising anindicating device, indeendent mechanisms for driving the indicatmgdevice in two mutually perpendicular directions, two electric motors anddifferential gear for driving said mechanisms, a'rheostat or controllingthe motors according to the direction of the vessel, a compass-needlepivoted centrally above the rheostat, and an arcuate scale upon the armof'the rheostat, the arm having a lamp and the needle having a mirrorfor reflecting a pencil of light onto the scale, for the pur osehereinbefore set forth.

6. Apparatus or indicating the course of a vessel, comprising anindicating device, independent mechanisms for'driving the indicatmgdevice in two mutually perpendicular d1- rections, two electric motorsand differential gear for driving said mechanisms, a rheostat forcontrolling the motors according to the direction of the vessel, acompass-needle pivoted centrally above the rheostat, and-an arcuatescale upon the arm of the rheostat, the arm having a lamp and the needlehaving a mirror for reflecting a pencil of light onto the scale; andother rheostats for controlling the motors according to the speed of thevessel, and to the speed and direction of prevalent tides, currents orwinds.

7. Apparatus for indicating the course of a vessel, comprisinganindicating device, independent mechanisms for driving the indicatmgdevice in two mutually perpendicular directions across a chart, electricmotors for actuatin said mechanisms, and a rheostat for contro ling themotors according to the direction of the vessel.

8. In a device of the character described, the combination with arheostat including an arm, of a lamp and scale carried by the arm, acompass-spindle, and a reflector carried by the compass-spindle andcoacting with said lamp to display a pencil of light on said scale.

In witness whereof I have hereunto set my hand in presence of twowitnesses.

HAROLD EDWARD SIIERWIN HOLT.

Witnesses:

BERTRAM H. T. MATTHEWS, WALTER E. Room

